Dr. Oz on controversial HCG diet: "This is not some crazy wacky idea"

Before preparing for my interview with Dr. Mehmet Oz, host of the Emmy-award winning The Dr. Oz Show, I must admit I had never heard of the HCG diet and couldn't quite wrap my head around. Think about it—people taking pregnancy hormones, living on just 500 calories a day and losing 30 pounds in a month! Too good to be true, right?

Dr. Oz says maybe not. After some new research, he says he's becoming "more supportive" of the weight loss regimen. "It's got to be done carefully, has to be done with a doctor who's reputable," he told me during a casual conversation in his New York City office. "We don't know enough to guarantee it's going to be effective. It's still an experiment but this is not some crazy wacky idea. It deserves to be studied."

Still, I had to ask Dr. Oz about some of the possible side effects (mood swings, hair loss) and whether the pregnancy injections could increase a person's risk of cancer. "There's all kinds of concerns about injecting any hormone into the body, and yet we know that for many conditions, it's quite effective. For men who have huge bellies and have no libido... we give them testosterone. With testosterone, they get their libido back... So when used correctly, these hormones do make sense. But you can't use them willy-nilly and they have to be studied carefully."

Oz says the goal should be an in-depth study to figure out if it works. "If it doesn't work, get rid of it... But if it works, imagine what that could do for the number one cause, preventable cause, of morbidity and mortality in this country, which is obesity."

Dr. Oz has faced a heavy dose of criticism for his support of the HCG diet, and for other weight loss tips he's embraced such as advocating green coffee bean extract as a weight loss tool especially because of his impact on everyday Americans. His sky-high popularity has led to the term "the Dr. Oz Effect" as many Americans run out and do whatever he suggests. This has both positive and negative implications, he told us.

Kelly Wallace is Chief Correspondent of iVillage. You can follow Kelly on Twitter (@kellywallacetv).